[PATCH] xrdb: Add actual querying capabilities to -query

[Michele Guerini Rocco]

> NTL it is better for the general look if you use a name
> for sign-off that is more easy to pronounce.
 
Sure, I've changed it to my real name.

> IMHO, the idea is good. I am struggling a bit with
> reusing the query option but thats not a showstopper.
> Lets see if a discussion comes up and if no one objects
> ping me next WE.

You're right, after reading the manual more carefully, it's clear this
would change the meaning of invocations like `xrdb -query filename` and
will likely break some script. It's better to just add a new option to
be sure it's backward compatible.

Here's the new iteration:
-- PATCH STARTS HERE --

The world is littered with broken grep commands because `xrdb -query`
can only dump the database and doesn't implement this simple search
feature. This patch adds a new `-get` option to search and print the
content of a single property by name.

Things I tested:

  - `xrdb -get prop` prints the value of `prop` when it exists in the
    resource database.

  - `xrdb -get prop` doesn't print anything when `prop` doesn't exist
    in the resource database.

  - `xrdb -get prop` doesn't leak any memory. I run it in valgrind
    with the `--leak-check=full` option.

PS: I think Sun took care of the fputs thing by now.

Signed-off-by: Michele Guerini Rocco <rnhmjoj at inventati.org>
---
 man/xrdb.man |  4 ++++
 xrdb.c       | 25 ++++++++++++++++++++++++-
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/man/xrdb.man b/man/xrdb.man
index 7ed14fc..85c748b 100644
--- a/man/xrdb.man
+++ b/man/xrdb.man
@@ -251,6 +251,10 @@ option.  The
 option can be used to merge the contents of properties back into the input
 resource file without damaging preprocessor commands.
 .TP 8
+.B \-get \fIname\fP
+This option indicates that the current content of the property matching
+\fIname\fP should be printed onto the standard output.
+.TP 8
 .B \-load
 This option indicates that the input should be loaded as the new value
 of the specified properties, replacing whatever was there (i.e.
diff --git a/xrdb.c b/xrdb.c
index 3f6e533..e93ce12 100644
--- a/xrdb.c
+++ b/xrdb.c
@@ -48,6 +48,7 @@
 #include <X11/Xatom.h>
 #include <X11/Xos.h>
 #include <X11/Xmu/SysUtil.h>
+#include <X11/Xresource.h>
 #include <stdio.h>
 #include <ctype.h>
 #include <errno.h>
@@ -84,6 +85,7 @@
 #define OPLOAD 4
 #define OPMERGE 5
 #define OPOVERRIDE 6
+#define OPGET 7
 
 #define BACKUP_SUFFIX ".bak"    /* for editing */
 
@@ -126,6 +128,7 @@ static char *editFile = NULL;
 static const char *cpp_program = NULL;
 static const char * const cpp_locations[] = { CPP };
 static const char *backup_suffix = BACKUP_SUFFIX;
+static const char *resource_name = NULL;
 static Bool dont_execute = False;
 static Bool show_cpp = False;
 static String defines;
@@ -786,6 +789,7 @@ Syntax(const char *errmsg)
             " -nocpp              do not use a preprocessor\n"
             " -E                  show preprocessor command & processed input file\n"
             " -query              query resources\n"
+            " -get name           get the content of a resource\n"
             " -load               load resources from file [default]\n"
             " -override           add in resources from file\n"
             " -merge              merge resources from file & sort\n"
@@ -984,6 +988,13 @@ main(int argc, char *argv[])
                 oper = OPQUERY;
                 continue;
             }
+            else if (isabbreviation("-get", arg, 2)) {
+                oper = OPGET;
+                if (++i >= argc)
+                    Syntax("-get requires an argument");
+                resource_name = argv[i];
+                continue;
+            }
             else if (isabbreviation("-load", arg, 2)) {
                 oper = OPLOAD;
                 continue;
@@ -1284,7 +1295,19 @@ Process(int scrno, Bool doScreen, Bool execute)
     }
     else if (oper == OPQUERY) {
         if (xdefs)
-            printf("%s", xdefs);        /* fputs broken in SunOS 4.0 */
+            fputs(xdefs, stdout);
+    }
+    else if (oper == OPGET) {
+        if (xdefs && resource_name != NULL) {
+            char *type = NULL;
+            XrmValue value;
+            XrmDatabase xrdb = XrmGetStringDatabase(xdefs);
+            Bool found = XrmGetResource(xrdb, resource_name,
+                                        resource_name, &type, &value);
+            if (found == True && value.addr != NULL)
+                printf("%s\n", value.addr);
+            XrmDestroyDatabase(xrdb);
+        }
     }
     else if (oper == OPREMOVE) {
         if (xdefs)
-- 
2.31.1
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